1. Field of the Invention
The present invention relates generally to contaminant removal from gas streams. In another aspect, the present invention relates to a process for removing one or more contaminants from a gas stream via contact with a regenerable sorbent.
2. Description of the Prior Art
In recent years, the demand for natural gas and other gas-phase fuels has increased substantially. At the same time, stricter regulations concerning allowable levels of certain components (e.g., sulfur species, acid gases, and other compounds of environmental concern) have been imposed, prompting fuel gas producers to develop economical methods of producing a compliant gas product.
One known method of treating a gas stream to remove undesirable components is to contact the gas stream with a physical or chemical solvent. Examples of chemical solvents include amines such as methyldiethanolamine (MDEA) and diethanolamine (DEA). Often, the selectivity of the chemical solvents can be problematic. For example, while amines are capable of efficiently removing hydrogen sulfide (H2S) from gas streams, the amines are generally not capable of absorbing other undesirable sulfur-containing compounds, such as, for example carbonyl sulfide (COS). As a result, additional process steps (e.g., COS hydrolysis) must be carried out before the gas stream can be used as fuel. In addition to removing H2S, most amines also remove carbon dioxide, which can place unnecessary processing loads on subsequent waste gas facilities. Further, most processes utilizing chemical solvents require extensive cooling of the incoming gas stream and often use large volumes of steam to remove absorbed contaminants from the solvent, which make these processes energy-intensive. Physical solvent-based processes are also highly energy-intensive and often require high operating pressures and/or low operating temperatures.
Accordingly, a need exists for an economic process for removing contaminants from a gas stream.